Aircraft typically include a plurality of flight control surfaces that, when controllably positioned, guide the movement of the aircraft from one destination to another. The number and type of flight control surfaces included in an aircraft may vary, but typically include both primary flight control surfaces and secondary flight control surfaces. The primary flight control surfaces are those that are used to control aircraft movement in the pitch, yaw, and roll axes, and the secondary flight control surfaces are those that are used to influence the lift or drag (or both) of the aircraft. Although some aircraft may include additional control surfaces, the primary flight control surfaces typically include a pair of elevators, a rudder, and a pair of ailerons, and the secondary flight control surfaces typically include a plurality of flaps, slats, and spoilers.
The positions of the aircraft flight control surfaces are typically controlled using a flight control surface actuation system. The flight control surface actuation system, in response to position commands that originate from either the flight crew or an aircraft autopilot, moves the aircraft flight control surfaces to the commanded positions. For example, during flight the pilot positions the primary flight control surfaces via a yoke or control stick and a pair of foot pedals. In particular, the pilot may control the position of the elevators, and thus aircraft pitch, by moving the yoke or control stick in a relatively forward or rearward direction. The pilot may control the positions of the ailerons, and thus aircraft roll, by moving (or rotating) the yoke or control stick in the left or right direction (or in the clockwise or counterclockwise direction,). Moreover, the pilot may control the position of the rudder, and thus aircraft yaw, by positioning a pair of right and left rudder pedals using their foot. It is noted that in addition to being used to position the rudder, the rudder pedals may also be used to apply the brakes to the landing gear wheels.
The rudder pedals are typically positioned in the aircraft and may be coupled to a system of mechanical mechanisms, such as rods and linkages, that are used to convert rudder pedal movements into rudder movement commands. These mechanical mechanisms are typically disposed below the aircraft cabin floor, and near the nose of the aircraft. Due in part to this location, the mechanical mechanisms are typically designed to withstand being struck by an object. For example, although highly unlikely, it is postulated that a bird (or other foreign object) could strike and penetrate the nose of the aircraft, and cause an inadvertent movement of the rudder pedals and/or rudder pedal mechanisms.
Presently, many aircraft address the postulated object strike event by incorporating break-away links within the mechanical mechanisms. These break-away links are normally in tension during operation. However, if the mechanical mechanisms are struck by an object and experience a compressive force, the links give way and do not, therefore, transmit a command to the rudder.
Although the present devices and methods for rudder pedals and associated mechanical mechanisms are generally safe, reliable, and robust, they do suffer certain drawbacks. For example, present devices may not be useful in current fly-by-wire flight control systems. Moreover, present mechanisms are configured such that brake operation may be undesirably influenced during rudder pedal operation.
Hence, there is a need for a rudder pedal mechanism that is configured to exhibit foreign object strike tolerance and that is useful in current fly-by-wire flight control systems and/or that allows for appropriate rudder control via the pedals without influencing brake operation, and vice-versa. The present invention addresses at least these needs.